1. Field of the Invention
The present invention relates to a team play analysis method, and in particular, to an optimal multi-resolution analysis method for extracting from a moving picture a team play sequence having certain size spatially and temporally, and for abstracting and displaying the team play sequence.
2. Description of the Related Art
Plays in team sports, such as soccer, rugby, American football, basketball, handball, hockey, ice hockey and water polo, unlike some other sports, tend to vary so rapidly as the game goes on. For these sports, the post-game study of team formations and player movements is of importance when team strategies and game results must be analyzed and understood.
To provide statistical information for team plays of field sports, conventionally, ranking services rely on an overwhelming concentration of human resources, to obtain and assemble scores and to analyze statistics. The performance of such indexing work, which requires a huge amount of workload, must perforce rely on a lot of inexperienced labor, and thus, under these circumstances, the information that is to be collected is limited to activities concerned, in most cases, with ball handling, since such events are easier for nonprofessional persons to judge.
Several studies are available wherein methods for visualizing team plays in field sports are disclosed. For example, in reference document 1 (“Qualitative Image Analysis of Group Behavior”, T. Kawashima, K. Yoshino and Y. Aoki, Proc. of IEEE CVPR, 1994), a method is proposed whereby a Gaussian filter is used to hierarchically extract a group, to describe the behavior of the hierarchical group in advance and to employ the pre-described behavior to analyze the actual activities in which the group engages. In reference document 2 (“Development of Motion Analysis System for Quantitative Evaluation of Teamwork in Soccer Games”, T. Taki, J. Hasegawa and T. Fukumura, Proc. of IEEE ICIP), a method is proposed whereby, while taking into account the direction of movement of runners, a first region that each player can reach is defined as a dominant region, and dominant region boundaries are displayed by using colored fields.
As is described above, according to the conventional visualization analysis, the only service that is provided is one that ranks players and teams during soccer games by concentrating on ball handling events. However, in reality, teamwork, which occurs at locations other than those at which ball handling events occur (locations at which there are no ball handling events), are significant and can greatly affect game progress. Especially, defense plays occur so often at such locations. For example, in the current ranking service for soccer, offense and defense events relative to a ball, and other events that have little or no direct relation to the actual plays, such as a foul and the awarding of a red card or a yellow card, can only be enumerated as events in the scoring table, and the indexes related to the play becomes mainly about offenses.
The ranks used in reference document 1 are determined temporarily with the presumption that the resolution can not be freely changed, and that the translation or interpretation of the group depends on the algorithm. Further, in reference document 2, since there is no ambiguous portion such as the “behavior” in reference document 1, the algorithm does not strongly affect the translation of an event. However, since the visualization of information is performed for each frame, the dominant regions in a time series must be manually interpreted in order to understand the team play.
As is described above, several methods have been proposed to fill the gap between the essence of the plays of the field sports and the indexing that is actually performed. However, as for a team play, that has a certain temporal size and for which the final interpretation of groups participating in an event and the collaboration within or between the groups must be done by human, there is no method present for appropriately handling the contents of the team play. For example, the method in the reference document 1 has many presumed portions, and is not appropriate for supporting the extraction of an event that is difficult to find. In reference document 2, while a display that corresponds to an actual play can be presented, it is limited to show a phenomenon for each frame, and visualization of a team play as the collaboration within and/or among player groups having a certain temporal size is not achieved.
To resolve the above conventional shortcomings, it is one object of the present invention to extract from a moving picture the team play that possesses width along the time axis, and to abstract and display it, so that the teamwork involved is easily discerned.
It is another object of the present invention to present, to a content creator, the teamwork within and/or among groups having multi-resolutions, so that more accurate information related to the team play can be obtained.
It is another object of the present invention to permit a content creator to select content that matches human interpretation, such as activities constituting the teamwork, so that content prepared by the content creator can be easily understood by a third party.